Axel Müller: One-dimensional hybrid nanoparticles based on cylindrical polymer brushes
|When:||Fr 17-06-2016 11:00 - 12:00|
Cylindrical (molecular) polymer brushes (CPBs) or ‘bottlebrush’ polymers, are versatile templates for the construction of nanorods, nanowires and nanotubes. CPBs possess side chains densely grafted from a linear backbone. Using the “grafting from” approach via ATRP or RAFT polymerization we have grown di- and triblock copolymers from a multi-initiator backbone, thus synthesizing well-defined core-shell and core-shell-corona CPBs with up to 4000 side chains.
We have used various functional core-shell CPB structures to generate hybrid nanowires of silica, semiconducting CdS and CdSe, superparamagnetic g ‑Fe2O3 and Fe3O4, catalytically active TiO2 or ions of rare earth metals inside the core of CPBs. These have a number of applications, including bioimaging. Incorporating electron acceptors in the backbone and electron donors in the “antenna” side chains leads to a single-molecular light harvesting system with tunable energy transfer efficiency.
Water-soluble and biocompatible hybrid silica nanowires and nanotubes were successfully synthesized by sequentially grafting a silica precursor monomer, 3-(trimethoxysilyl)propyl acrylate (APTS) from a backbone. Hydrolytic crosslinking of the PAPTS block rendered a silica core with a water-soluble corona, which can host Au or Pd nanoparticles for catalysis. Uniform silica nanowires were achieved by pyrolysis. The length as well as the diameter of silica nanowires is well-defined. Growing triblock terpolymers with PAPTS middle block from the backbone finally resulted silica nanotubes.